Types and Installation of Factory Electrical Distribution Boxes

Electrical distribution boxes include main distribution boards, sub-distribution boards, consumer units, meter panels, and specialized enclosures, each designed for specific installation needs and environments.

Common Types of Distribution Boxes

1. Main Distribution Board (MDB) The MDB is the primary control panel for a building or facility. It receives the main high-amperage supply from the utility or transformer and distributes it to sub-distribution boards and major loads. It typically contains the main breaker, busbars, and outgoing feeders, and is used in large commercial buildings, industrial plants, and high-rise residential complexes .
2. Sub-Distribution Board (SDB) SDBs receive power from the MDB and distribute it to smaller circuits within a specific area or floor. They are commonly used in commercial and industrial settings to manage localized loads efficiently .
3. Consumer Unit / Load Center Often used in residential installations, a consumer unit (also called a load center) houses circuit breakers or fuses for individual circuits. It provides protection against overcurrent and short circuits and may include RCDs or RCBOs for additional safety .
4. Meter Panels Meter panels are designed to accommodate utility meters and may include multiple meters for multi-tenant buildings. They allow separate metering and distribution for each unit or tenant .
5. Panel Fuse Banks and Unitized Panels These are specialized enclosures that contain fuses or modular units for industrial or commercial applications. They are often used where modularity and easy replacement of protective devices are required .
6. Transfer Switches and Enclosed Switchgear Transfer switches are used in critical facilities to switch between utility and backup power sources. Enclosed switchgear provides high-voltage or medium-voltage distribution with integrated protection and control .
7. Junction Boxes and Specialized Enclosures Junction boxes (J-boxes) are used to protect wire splices and connections. Specialized distribution boxes are designed for harsh environments, outdoor use, or decentralized installations, often with IP or NEMA ratings for moisture, dust, and impact protection .

Selection Considerations

• Application: Residential, commercial, industrial, outdoor, temporary power, solar, or machinery.
• Supply System: Single-phase, three-phase, AC, DC, TN, TT, IT, or local earthing system.
• Number of Circuits: Include spare ways for future expansion.
• Protective Devices: MCBs, RCDs, RCBOs, fuses, isolators, surge protection.
• Rated Current and Short-Circuit Capacity: Based on actual load and fault current.
• Internal Layout: Busbar type, neutral and earth bar arrangement, DIN rail space, wiring room, and heat dissipation.
• Standards Compliance: IEC 61439, IEC 60670, IEC 60898, UL/NEC, BS 7671, or regional codes .

Summary

The series of electrical distribution boxes ranges from residential consumer units and meter panels to industrial main and sub-distribution boards, panel fuse banks, and specialized enclosures for harsh or decentralized environments. Choosing the right type depends on the application, load requirements, protective devices, and compliance with local electrical standards, ensuring safe, efficient, and reliable power distribution .